BMI-dependent sex differences in atrial tachyarrhythmia recurrence despite greater low-voltage substrate in women: a SUPPRESS-AF subgroup analysis
N Tanaka, M Okada, M Masuda, T Watanabe, H Minamiguchi, Y Egami, T Oka, A Sunaga, K Iwasa, K Tanaka, K Iwakura, T Dohi, K Inoue, Y Sotomi, Y SakataAbstract
Background
The SUPPRESS-AF randomised trial showed no significant overall reduction in 1-year atrial tachyarrhythmia recurrence with additional left atrial low-voltage-area (LVA) ablation versus pulmonary vein isolation (PVI) alone in persistent atrial fibrillation (AF) with LVAs, underscoring the need to understand outcome heterogeneity.
Purpose
To assess whether body mass index (BMI) modifies sex differences in 1-year recurrence and LVA burden.
Methods
Subgroup analysis of 341 participants with persistent AF and LVAs covering >=5 cm2 of the left atrial surface on a post-PVI voltage map, randomised 1:1 to PVI plus LVA ablation or PVI alone. LVAs were defined by bipolar voltage <0.5 mV. AF/atrial tachycardia (AT) recurrence was assessed by scheduled 24 h Holter monitoring at 6 and 12 months and twice-daily portable electrocardiogram recordings from 6 to 12 months. The primary endpoint was AF/AT recurrence or initiation of antiarrhythmic drugs within 12 months after ablation (90-day blanking period). BMI was dichotomised at the median (23.3 kg/m2); exploratory BMI bands were <21, 21-<23, and >=23 kg/m2.
Results
Of 341 patients, 167 were women. In the lower-BMI stratum (<23.3 kg/m2; n=169), 1-year recurrence was lower in women than men (36% vs 52%; log-rank P=0.034; hazard ratio 0.61, 95% CI 0.38-0.98). In the higher-BMI stratum (>=23.3 kg/m2; n=172), recurrence did not differ by sex (46% vs 42%; P=0.83). In the lower-BMI stratum, women had smaller left atrial surface area but greater LVA burden than men (surface area 143.9 [124.8-174.7] vs 154.9 [134.9-184.7] cm2, P=0.030; LVA area 17.8 [10.1-26.7] vs 12.0 [8.1-20.8] cm2, P=0.006; LVA area percentage 11.3 [6.9-19.7] vs 7.3 [5.4-12.0]%, P<0.001). In exploratory BMI bands, the sex difference was most pronounced at BMI 21-<23 (27% vs 55%; P=0.014) and absent at BMI <21 and >=23.
Conclusion
In persistent AF patients with LVAs, sex differences in 1-year recurrence were confined to lower BMI, despite a greater voltage-defined substrate burden in women. BMI-dependent sex-specific mechanisms beyond LVA extent may contribute to outcome heterogeneity and support phenotype-driven risk stratification in LVA-positive persistent AF.